REQUIRED_INTERFACE on the same subnet?

I've got a verified network bottleneck on one of my Netbackup redhat linux clients. Production data volume is causing backup performance to suffer, and backup performance is critical to keep oracle archive redo logs from filling up available filesystem space.

There is a second physical NIC available.

We do not have a dedicated backup subnet, or this would be easy.

When using the REQUIRED_INTERFACE directive in bp.conf, do the network interfaces have to be on different subnets?

For example, "eth0" is 10.1.1.1, and we add "eth1" as 10.1.1.2. Will "REQUIRED_INTERFACE=10.1.1.2" work properly, and send the backup data out the 10.1.1.2 interface?